Alcohol and other drug use disorders among youth present a tenacious public health problem. Despite considerable advances in the development of efficacious treatments for adolescents with these disorders, relapse is very common (Dennis, Godley et al, 2004) and only about one third of adolescents exhibiting a broad range of substance-related involvement and impairment engage in any continuing care (Godley, Godley et al, 2001). Freely available community resources, such as Alcoholics Anonymous (AA) and Narcotics Anonymous (NA) have been shown to be helpful relapse prevention and recovery resources and also appear cost-effective (Humphreys and Moos, 2001;2007) for many different types of adult patients with substance use disorder (SUD). Evidence from adult studies also suggests that the use of various forms of professionally-led Twelve-Step Facilitation (TSF) can enhance substantially the likelihood that patients with SUD will participate in peer-led 12-step fellowships (Kahler et al, 2004;Kaskutas et al, 2009;Nowinski et al, 1992;Sisson and Malams, 1982;Timko, DeBenedetti et al, 2006;Walitzer, Dermen, et al, 2008). However, no randomized controlled TSF investigations have been conducted among adolescents, despite evidence that youth almost uniformly receive referrals to AA/NA groups (Kelly, Yeterian et al, 2008;Knudsen et al, 2008) and appear, in correlational studies, to benefit from participation (Chi, Kaskutas et al, 2009;Kennedy and Minami, 1993;Kelly, Brown et al, 2008). Experimental study designs are sorely needed to properly eliminate the self-selection biases that plague correlational studies. Given the widespread use of 12-step referrals and related treatment approaches in the United States among adolescent treatment providers (Drug Strategies, 2003;Knudsen et al, 2008), such a study will critically inform our knowledge of the appropriateness and relative efficacy of TSF approaches for youth and, if shown to be efficacious, will eventually provide helpful clinical tools that will exert a widespread community impact. The primary objectives of this project are to develop a manualized, developmentally-appropriate, intervention that combines MET/CBT with TSF to form an "integrated TSF" ("iTSF") treatment for adolescents and to obtain an effect size estimate for this intervention compared to an existing evidence-based treatment (MET/CBT) that will include a standard referral to AA/NA. The effect size estimates from this Stage I research would provide the foundation for a future application to conduct a large-scale, Stage II, randomized clinical trial that would be powered to test mediational mechanisms of action. Ultimately, we expect this program of research will result in a well-specified, efficacious intervention that could be readily disseminated.